I. Field of the Invention
The present invention relates to an electric offset staple driving device.
II. Background of the Invention
The use of an electric tool to drive staples or the like is normally accomplished with a device such as depicted in U.S. Pat. No. 4,005,812 to Doyle et al. In such a device, a vertically disposed coil is activated to drive a centrally located armature down through the coil toward the staple to be driven. In the above-noted patent, the blade engaging the staple is located centrally in the armature and, therefore, the distance between the edge of the stapler and the location where the staple is driven is greater than half the thickness of the coil. In applications where it is desired to place the staple up against a vertical surface, the location of the blade within the center of the coil is at a significant disadvantage. Therefore, staplers have been constructed having the driving blade offset from the center of the coil, such that the driving blade is more closely associated with the front edge of the stapler. Such a device is depicted in U.S. Pat. No. 3,786,978 to Manganaro.
In such a device, the driving blade is linked to the armature by means of a rigid member that propels the driving blade downward with the downward movement of the armature. Because the driving blade is offset from the vertical axis of the coil, a torque is created when the driving blade strikes the staple. Since this torque can cause the armature to bind or jam within the coil, means are provided for restraining the movement of the armature in a radial direction from the central axis of the coil. In the above-noted Manganaro patent, the device includes an upper support that surrounds a vertical extension of the armature to provide radial support for the armature. The existence of this radial support and the elements necessary to confine the armature in a radial direction complicate the structure and increase the cost of production of such a device. As is apparent from the Manganaro patent, this also increases the height of the device which in certain applications can be detrimental.
Therefore, it is the primary object of the present invention to provide an offset stapler that effectively operates without the above-noted shortcomings of the prior art. Specifically, one of the objects of the present invention is to provide an offset electric stapler that is inexpensive to manufacture, has a minimum of moving parts and operates effectively without the shortcomings of offset electric staplers that require radial support mechanisms for the armature.
Other objects and advantages of the invention will be apparent from the description of the preferred embodiments or may be learned by practice of the invention.